Method for producing topstitching



Sept. l2, 1939. v. J. slGoDA METHD FOR PRODUCING TOPSTITCHING 2 Sheets-Sheet l Filed NOV. 17, 1936 SepLrlZ, 1939. v. J. slGoDA 2,172,569

METHOD FOR PRODUCING TOPSTITCHING Filed Nov. 17, 1936 2 Sheets-Sheet 2 INVENTOR M570/Q f 5/6 BYZ-@Q ATTORNEY Patented Sept. 12, 1939 UNITED STATES PATENT OFFICE METHOD FOR PRODUCING TOPSTITCHING Application November 17, 1936, Serial No. 111,215

1 Claim.

My present invention relates to top or overedge stitching, and the invention relates more particularly to improved method steps and means under which, in one continuous sewing treatment, layers of fabric are brought together along a folded edge where they are top or overedge stitched, then their free edge portions are pinked or trimmed, and finally the trimmed-off waste portions are positively disentangled and separated from the united materials.

One object of the invention i's to provide a novel mode of treatment which may be carried out in -a high speed topstitching and pinking sewing machine. The high speed sewing mal chine which may be used for carrying out the invention may produce either zigzag topstitched seams or simple, straight seams. The well known Singer sewing machines, for instance, are made in types having zigzag topstitching mechanism and having simple, straight or plain stitching mechanism. The apparatus disclosed herein is adapted to be fitted to these sewing machines without any change therein, except to substitute new presser-feet for those with which these machines are normally equipped.v

Another object of the invention is to so form, fold and compact the folded edge of a hem that a neat, narrow and accurate topstitched seam may, at high speed and without specially skilled operators, be produced in uniting the most delicate of garment fabrics, and also that the layers of fabric being united will not creep or stretch relatively to one another but will be smoothly fitted and maintained until. they are secured together by the seam. The object in this respect is to produce a smooth, elastic topstitched seam unmarred by deformations such as end curls, puckering, little ridges or indentations. The closely pressed folded edge which I produce in accordance with my invention, preparatory to the stitching, may also be used to form a relatively wide zigzag topstitched seam and in connection with relatively coarse materials.

After the layers of fabric have been united by 5 the topstitched seam, the raw edges which come on the concealed side are pinked by passing them between two rotary elements which also aid in the feeding operation. One of these elements is a bottom pinking device which consists of a fiat, 50 narrow, endless pinking ring or cutter, disposed to rotate horizontally, and to pink in the path of the straight-away feed, parallel with the seam. A still further object is to so locate this bottom pinker in series with respect tothe straightaway 55 feed, that the trimmed-off portions will be positively disentangled and removed a distance from the seamed fabrics.

In addition to the foregoing objects and others, I provide as hereinafter set forth, an apparatus for continuously and automatically carrying out the invention, the same embodying a number of special advantages the purpose and object of which are to improve the mode of operation and practical application of my method in general.

'I'he principles of the invention and the preferred method and mode of carrying the same into effect in a practical way may be best understood by reference to the accompanying drawings in which the apparatus shown is presented as an example, and in which:

Figure lis a top plan View and partial section showing an apparatus for carrying out my im proved method steps in connection with a zigzag topstitching and trimming sewing machine;

Fig. 2 is a side elevational view looking toward the lower longitudinal side edge of Fig. 1;

Fig. 3 is an enlarged fragmental sectional view taken on the line 3-3 ofl Fig. l, showing sections of fabric on their way through the folder-guide;

' Fig. 4 is a cross sectional View on the line 4 4 of Fig. l, showing the waste diverting grooves;

Fig. 5 is a cross sectional View taken on the line 5 5 of Fig. 1, showing the formed hem on the upper fabric section and also showing adjoining the hem the folded edge in process of formation;

Fig. 6 is a cross sectional View taken on the lline 6-6 of Fig. 1, illustrating how the folded edge is compacted and seamed and the free edge portions trimmed, and also how from the compacted folded edge the upper section is elevated to pass freely over the pressure mechanism;

Fig. 7 is a fragmentary top plan view showing two pieces of fabric being formed, i'ltted stitched, trimmed and the waste separated, by successive steps in one passage vthrough the apparatus;

Fig. 8k is a fragmentary top plan view, partly broken away, showing sections of fabric united by a zig zag top-stitched seam and with the free ends trimmed; and

Fig. 9 is a view similar to Fig. 8, but showing the sections united by a simple, straight seam.

Describing the invention with reference to the drawings, in which I have shown for purposes of illustration, an apparatus suitable for application to well known types of Singer sewing machines (for instance, high speed models class No. 107101, class No.,143w1 and Class No. 95), I5 denotes the cloth plate of the sewing machine, I6 the four-motion feed dog, I1 the transversely vibratory needle for producing zigzag stitches and |8 the usual supporting shank for a presserfoot. The needle mechanism and the presserfoot shank are supported and operated in well known manner for carrying out their usual functions, no change being made in this respect.

I9 denotes a base plate which supports various parts of the apparatus. This base plate may be mounted upon the top surface of the cloth plate but it is preferably recessed in the cloth plate and so as to make flush the top surfaces of the two plates as herein illustrated. Said base plate I9 includes as part thereof a throat plate portion 20 (Fig. 6) having the usual openings for working parts and the throat plate portion replaces the usual throat plate.

Mounted in an annular raceway .2| in the base plate I9 for rotation therein in a horizontal plane is a flat, endless pinking ring or trimming cutter 22 having outer and inner peripheries 23 and 24, with a top surface 25 therebetween on which in juxtaposition to the outer periphery are raised or upwardly presented cutting teeth 26. This endless ring forms a bottom pinking cutter. Its teeth may be of any suitable form but are herein illustrated as having a zigzag form to produce the usual V-shaped pinking cuts 21 on the free edges of fabrics. In the present embodiment, power for operating the pinking ring is taken from the feed-dog I6, each fabric feeding movement of the feed-dog giving Vthe pinking ring a synchronous movement in the direction of the arrow 28. The usual four-motion action of the feed-dog may be used to give the pinking ring intermittent movement in the same direction.

In the present illustrative example, the feeddog is made with an upwardly projecting tongue 29 freely movable vertically in an opening 30 in the annular clutch ring 3| disposed for actuation n the base plate within the circle of the pinking ring. The feeding and retracting movements of the feed-dog give to the clutch ring to and fro .movements and suitable clutch mechanism (not shown) between the clutch ring and pinking ring causes the latter to be actuated in the direction of the arrow 28 with the feeding .movements of the feed-dog. Any suitable clutch mechanism may be used to impart intermittent movement to the pinking ring and in my application for Letters Patent of the United States, Serial No. 45,787, led October 19, 1935, I disclose several types of clutch mechanism suitable for the purpose.

- Cooperating with the pinking ring to pink fabrics is a freely rotatable roller 32 which is supported-onthe end of an arm 33 carried by a rock shaft 34 adjustably arranged in a bracket 35 mounted upon the base plate behind the'Vv presser-foot. The fabric to be trimmed is seized by the pinking ring and roller, fed lalong under the movements of the pinking ring and trimmed thereby, the roller pressing the fabric into the raised cutting teeth and being rotated by the rotative movements of the pinking ring. The point at lwhich the roller cooperates with the pinking ring to do the trimming is very close to the une of stitching produced by the needle mechanism.

To accomplish this, theV presser-foot 36 is made needle very close lt'o the point at which the pinking is done. Moreover, in order to permit the trimming action to take place as closely as possible to the line of the seam and parallel therewith and also as close as possible to the feed-dog and-presser-foot, while at the same time providing such clearance with respect to the presserfoot as will admit of the use along the face of the roller of a shield-guide 39 for the top section of the fabric, the axis 40 of the roller is mounted at an angle, being inclined inwardly and downwardly with respect to the circle of the pinking ring, and the periphery of the roller is beveled as shown so-as to contact with the entire width of the cutting teeth.

4| denotes a folder-guide of usual type for forming an under hem on a fabric which is passed therethrough. In the present instance, this folder-guide is mounted upon the base plate in a position in frontof the sewing mechanism and serves to form upon the upper fabric section 42 an under hem 43 which it places upon the iiat marginal portion 44 of the lower fabric section 45, fed at upon the horizontal platform 46 of said folder-guide and with the marginal portion 44 passing underneath the projecting guide 41.

The presser-foot is made with a forwardly projecting toe 48 which projects at right-angles to the straight transverse front edge 49 of the lateral toe portion 31 and at the outer side thereofl remote from ythe finger 50 projecting rearwardly from the folder guide. 5| is a vertically disposed blade-guide the shank 52 of which is mounted upon the toe portion 48 through a screw and slot connection 53, whereby the blade-guide is adjustable along the front edge 49 at rightangles thereto, between the side edge 54 of the toe portion 48 and a wall 55 which forms part of the shield-guide 39. The wall 55 rises upwardly as it proceeds rearwardly so that the shield-guide of which it is a part may cover over or partially cover over the roller 32. These parts, the special arrangement and relative adjustment thereof are important as they determine the fitting together and maintenance of the layers of fabric until the sewing thereof. They are especially advantageous in fitting together light, delicate fabrics so that a neat, rm, smooth seam will be produced withoutpu'ckering, end curls and without hollows or ridges due to unequal, forced or rapid feeding in which one fabric layer is caused to creep or stretch relatively to the other just before or at the time of stitching. The vertically disposed blade-guide 5|, finely adjustable toward and away from thewall 55, extends under the finger 50 and under the lateral toe portion 31. It is set in definite relation to thefline or lines of stitching to be produced by the stitching mechanism and determines the precise position of the folded edge 56 with respect to the line of stitching by which the needle mechanism unites the layers of fabrics. The lower fabric section 45 passes underneath the blade-guide and presser-foot. The upper fabricv section 42 passes upwardly over the rising wall 55 and shield-guide 39. The folded edge 56,

which also passes underneath the presser-foot,

is guided thereunder toward the needle by the blade-guide 5|. The marginalportion 44 and hem 43 pass over the base plate and underneath the shield-guide to be seized and edge trimmed by the pinking ring and cooperating roller. The rising wall 55, rising in the direction of the straightaway feed and at an angle with respect to the blade-guide and presser-foot, keeps the feeding upper fabric section in condition to supply to the folded edge any deficiency of material and as well to take up therefrom any surplusage of material. In other words, the rising wall in conjunction with the blade-guide and presser-foot serves to smooth out the material and maintain a full folded edge 56 in contact with and guided by the blade-guide.

As the upper .section emerges from the folderguide, the bight 51 within the folded-edge 56 is widely open. As thev folded-edge moves along the blade-guide, the bight closes up until the opposing layers are in contact. During this time, adjustment of the material from the foldededge onwards over the rising wall takes place to provide the desired smoothness for the seam base. Then in proceeding under the presserfoot and just prior to the stitching, the foldededge is compacted with the bight tight closed so that the layers feed together practically as one piece until united by the stitching.

'I'he stitching having been accomplished, the united fabrics in their straightaway feeding action, carry the free edges ofthe marginal portion 44 and superimposed hem 43 between the pinking ring and roller for the trimming operation. It is to be remarked in this connection that the trimming operation, which takes place after the seam has been completed, with the upper fabric section feeding over the elevated shield-guide 39 and with the lower fabric section feeding over the base plate and up over the bracket 35, does not cause any pulling or twisting upon the formed seam. The flat horizontally disposed intermittently operated pinking ring in cooperation with the roller, makes a sharp trim parallel with the seam and without disturbing the normal straightaway feed.

It will be noted from reference to Fig. 6 of the drawings that the cutting edges of the pinking ring lie in a horizontal plane above the plane of the fabric section 45. Thus immediately after the stitching operation the laterally projecting edge portions of the two fabric sections are engaged between the teeth of the pinking ring and pressure roller 32 and are thereby upwardly offset above the general plane of the fabric section 45. Therefore, in the gripping and feeding action of said cutting ring and pressure roller the fabric parts forming the fold 56 will be relieved of lateral strain, tending to distort and weaken the seam. 'I'his would otherwise be inevitable owing to the fact that the cutting teeth move in a horizontal arcuate path.

The quick intermittent movements of the pinking ring in the direction of the arrow 28 draws the trimmed-off portions away from the trimmed edges and through such drawing action separates .and disentangles any fibers of the waste that may be adhering to the trimmed edges. The base plate is provided with a series of waste grooves 58 which extend rearwardly from the outer periphery 23 of the pinking ring and at an angle to the straightaway feed. 'Ihe trimmedoff portions, dust and ravelings are caught in these grooves in which through the rotary feeding movements of the pinking ring,they are forced rearwardly until they fall from the base plate.

The sewing machine being in operation, the fabric sections 42 and 45 are introduced in the usual way into the folder-guide 4I by means of which the hem 43 is underfolded and disposed upon the fiat marginal portion with the folded-edge 56 passing to contact longitudinally along the blade-guide 5l, adjustment of which is previously made to the precise position desired with relation to the line of stitching to be produced in order to determine the precise character of the seam. At this time, the bight 5l within the folded-edge is openv or substantially so.

In this process the upper fabric section 42 (save for the portion thereof folded or being folded) passes over the folder-guide and onto the shield- The fabric section 45 (save the portion thereof passing over the platform 46 and underneath the folder-guide) moves in fiat position over the cloth and base plates.

As soon as the fabrics are moved under the presser-foot and engaged with the feed-dog, they are automatically fed. At this time the upper fabric section 42 is moving up over the rising Wa1l55 and shield-guide 39 so that the foldededge 56 will be automatically smoothed, fitted and compacted along the blade-guide in the precise position in which it is to be united by the line or lines of stitching with the lower fabric section 45. The wall 55 of the shield-guide, rising sharply with respect to the blade-guide and presserfoot and alongside the presser-foot, keeps the rapidly feeding material in such quickly yieldable condition that the folded-edge portion is smoothly fitted along the blade-guide, and such edge under the presser-foot is compacted with a tight-closed bight before being presented to the needle mechanism'.

In zigzag stitching, a line of stitches 59 may be made along the very nose 60 of the folded-edge, another line 6I upon the lower fabric section just clear of the nose, with stitches crossing the nose from one line to the other, all in known manner and as illustrated in Fig. 8. With my mode of treatment (the transversely vibratory needle mechanism having been properly set), the lines 59 and 6I may be brought very close together to produce a very smooth, narrow topstitched seam.

Such a seam is advantageously used in uniting y guide (and also the set of the transversely vibratory needle mechanism). Both relatively narrow and relatively wide seams may also be used in uniting coarse materials.

As illustrated in Fig. 9, a single seam 62 may be used to unite the fabric sections instead of a zigzag seam. It will of course be understood by those skilled in the art that in order to produce a plain or single seam, a sewing machine having needle mechanism designed for such purpose will have to be used.

Whatever the specific character of the topstitched seam, the free edges of the hem 43 and marginal edge portion 44 may be trimmed together parallel with the formed seam by Passing them between the pinking ring and roller as previously described. The pinking ring with its cooperating roller automatically produces sharp V-cuts 21, and finally the movements of the pinking ring taken in conjunction 4with the waste grooves 58 positively separates and removes the trimmed-off portions, dust and waste from the trimmed edges of the united fabrics.

While I- have illustrated and described my invention as comprising a particular mode of treatment and as taking a particular form, it will be understood that changes and alterations may be made in the particular details and steps set forth without departing from the spirit of the invention, and hence I do not limit myself to the particular details and steps set forth, but consider myself at liberty to make such changes and alterations as fairly come within the scope of the appended claim.

I claim:

The method of seaming and trimming fabrics which consists in progressively feeding two' layers of fabric over a horizontal surface, forming a fold 10 in one fabric layer and compressing the opposed parts of the fold upon each other and upon the other layer of fabric, with superimposed edge portions of said fabric layers projecting laterally.

from said fold, then stitching said fold to said other fabric layer, and, immediately after stitching offsetting said edge portions above the plane of the latter fabric layer and engaging the same between relatively moving feeding members and simultaneously forming pinking cuts therein.

VICTOR J. SIGODA. 

